Auditory Channels Research Articles

Using Game Engines for Visuo-Haptic Learning Simulations

Technological advances have been the main driver of enhancing human–computer interaction and interactive simulations have experienced exponential growth in recent years. However, visual and auditory channels are usually the only ones considered for educational simulations even though the sense of touch is also an important one. Touch allows us to recognize and interact with our surroundings. A common way to develop a visuo-haptic simulation in the area of interactive systems is by using a graphic and physics-based engine orchestrated with a haptic rendering framework. However, new solutions, such as professional game engines, have enabled the development of high-quality applications in much shorter time. In this paper, a novel architecture for fast development of interactive visuo-haptic applications in game engines is discussed. To validate the proposed architecture, the Haptic Device Integration for Unity (HaDIU) plugin was implemented. Simulations were implemented to verify the operability of haptic devices. Each scenario was properly modelled and has different haptic objectives. Furthermore, to validate that the usage of this approach provides better visualizations than an existing single purpose application, an experimental study was performed. Results suggest that by using this approach faster development of interactive visuo-haptic simulators can be achieved than using traditional techniques.

LISTENING IN NATIVE LANGUAGE TRAINING OF FUTURE CIVIL DEFENSE OFFICERS

Introduction. A modern higher school wants a teacher to use effective teaching methods that ensure the intensive development of such professionally important skills for future civil defense officers as listening ones, in particular, to perceive a text (using visual and / or auditory channels), to comprehend, to select the necessary from the heard / read information, to reproduce, and to interpret. The problem under study was especially relevant in the conditions of updating higher education. Purpose. Analysis of modern methodological foundations of listening and determination of methods and techniques for the formation of auditory skills in the process of native-language training of future civil defense officers. Results. The article deals with hermeneutic and communicative-pragmatic approaches in the linguo-didactic aspect. The outlined approaches allow us to determine the methodological basis for auditory skills formation since they help resolve the problem of understanding and interpretation of the text, as well as analyze linguistic facts in view of the social, psychological, and cultural characteristics of the speaker and the listener. The contents of “listening” and “active listening” concepts are clarified; the basic psychological mechanisms, psycholinguistic factors of formation and development of cadets’ / students’ listening skills in the process of native-language training are determined. The author considers various classifications of listening in domestic linguistics, namely: global, detailed, critical and non-reflective / reflexive ones and stresses the urgency of the critical type of listening for the future civil defense officers, as it implies a reaction to what has been heard, its interpretation, and critical reflection. The structure of listening which includes such components as: perception, comparison-recognition, and understanding, is characterized; the sequence of actions and operations of listening as a type of educational activity (perceptual, thinking, mnemonic, reflexive ones) are revealed. The basic requirements for texts for listening are analyzed; the most effective methods of working with a text are determined; alternatives to listening using video materials and movies are suggested. Conclusion. Listening, including correctly selected texts or video materials and post-textual exercises, in the process of native language training of future civil defense officers, allows to solve a number of linguistic and methodo-logical problems: it develops hearing and memory, trains the ability to highlight the most informative parts of the message, to correlate the text with the situation of the message, and to interpret what has been heard.

Psychobiological Responses Reveal Audiovisual Noise Differentially Challenges Speech Recognition

In noisy environments, listeners benefit from both hearing and seeing a talker, demonstrating audiovisual (AV) cues enhance speech-in-noise (SIN) recognition. Here, we examined the relative contribution of auditory and visual cues to SIN perception and the strategies used by listeners to decipher speech in noise interference(s). Normal-hearing listeners (n = 22) performed an open-set speech recognition task while viewing audiovisual TIMIT sentences presented under different combinations of signal degradation including visual (AVn), audio (AnV), or multimodal (AnVn) noise. Acoustic and visual noises were matched in physical signal-to-noise ratio. Eyetracking monitored participants' gaze to different parts of a talker's face during SIN perception. As expected, behavioral performance for clean sentence recognition was better for A-only and AV compared to V-only speech. Similarly, with noise in the auditory channel (AnV and AnVn speech), performance was aided by the addition of visual cues of the talker regardless of whether the visual channel contained noise, confirming a multimodal benefit to SIN recognition. The addition of visual noise (AVn) obscuring the talker's face had little effect on speech recognition by itself. Listeners' eye gaze fixations were biased toward the eyes (decreased at the mouth) whenever the auditory channel was compromised. Fixating on the eyes was negatively associated with SIN recognition performance. Eye gazes on the mouth versus eyes of the face also depended on the gender of the talker. Collectively, results suggest listeners (1) depend heavily on the auditory over visual channel when seeing and hearing speech and (2) alter their visual strategy from viewing the mouth to viewing the eyes of a talker with signal degradations, which negatively affects speech perception.

A Structure Design of Virtual and Real Fusion Intelligent Equipment and Multimodal Navigational Interaction Algorithm

Virtual experiments have become an interesting research topic in the field of education. However, we found that there are some limitations in the current virtual experiments: first, the researchers used the virtual effects of the simulation to represent the virtual experiments, which led to decrease the immersion of the user's simulated experiments; second, most of the virtual experiments are only mouse or touch screen interactive mode, which reduces the realism of user simulation experiments; third, students independently explore the experimental operation process and spend too much time simulating the experiment, which leads to problems such as overloading the operation and low interaction efficiency. In order to solve the above problems, we propose and implement a multimodal navigational interaction virtual and real fusion chemistry laboratory (MNIVRFCL). We design a new sensing structure intelligent equipment and propose a multimodal navigational interaction algorithm (MMNI) based on auditory and tactile channel, which are verified and applied in MNIVRFCL. The MMNI algorithm can detect user's specific behaviors to understand their behavioral intentions, and then the system guide and rectify users' current correct or incorrect behaviors in the form of voice navigation broadcasts. Finally, we achieve the purpose that students can use virtual and real fusion interactions through tactile and auditory channels, they can independently complete simulations and learning experiments based on experimental navigation. The experimental statistic results show that system's successful understanding of intention is 91.48%, and prove the MNIVRFCL operational load reduce by 23.81% compared to the pure virtual experiment, it can reduce the time consumption and improves the students' interaction efficiency.

Augmented Reality Application for Hand Motor Skills Rehabilitation

The paper presents an augmented reality based solution for hand movement rehabilitation using visual and tactile feedback. The proposed approach to the rehabilitation process combines the effects on visual, auditory and tactile channels of perception and simulation scenarios. In order to develop a hand movement model capable of solving rehabilitation tasks there was studied the concept of immersive virtual reality. Original 3D models and scenes have been developed to simulate the basic hand positions and motor functions. To provide efficient hand motion fixation it is recommended to implement a mechanical position tracking system based on a sensor glove improved by using the resistive transducers. Augmented reality is implemented to inspire and motivate the user to perform the required exercises by generating the corresponding pictures. Personalized comparative analysis of the dynamics of the patient's initial condition and rehabilitation results help to study the motor function and restore everyday skills. The proposed solution allows achieving accuracy and adequacy of fingers movements sufficient to satisfy the requirements of medical rehabilitation applications.

A neural ensemble correlation code for sound category identification.

Humans and other animals effortlessly identify natural sounds and categorize them into behaviorally relevant categories. Yet, the acoustic features and neural transformations that enable sound recognition and the formation of perceptual categories are largely unknown. Here, using multichannel neural recordings in the auditory midbrain of unanesthetized female rabbits, we first demonstrate that neural ensemble activity in the auditory midbrain displays highly structured correlations that vary with distinct natural sound stimuli. These stimulus-driven correlations can be used to accurately identify individual sounds using single-response trials, even when the sounds do not differ in their spectral content. Combining neural recordings and an auditory model, we then show how correlations between frequency-organized auditory channels can contribute to discrimination of not just individual sounds but sound categories. For both the model and neural data, spectral and temporal correlations achieved similar categorization performance and appear to contribute equally. Moreover, both the neural and model classifiers achieve their best task performance when they accumulate evidence over a time frame of approximately 1–2 seconds, mirroring human perceptual trends. These results together suggest that time-frequency correlations in sounds may be reflected in the correlations between auditory midbrain ensembles and that these correlations may play an important role in the identification and categorization of natural sounds.

Establishing an audibility sensitivity rule for low-frequency tone complexes in noise

Predicting the audibility of a sound over ambient noise is an important step to assess its impact on observers. One anticipated need for such predictions is the desire to operate aerial vehicles in urban surroundings close to the public. The increased audibility of a complex set of low-frequency tones due to the recruitment of a number of independent auditory channels has been investigated in this work. Three experiments were carried out to establish a sensitivity rule for these signals. During the main experiment, the masked threshold for signals consisting of one, two, and three tone components (55, 120, and 200 Hz) were measured. As expected, the thresholds identified during this experiment point to an increased sensitivity relative to a single-tone case. However, these increases were greater than similar findings by other researchers at higher frequencies. Two follow-up experiments examined the effect of larger frequency separation between tones and their intermodulation. The findings of these experiments attribute part of the audibility improvement to biased estimation of the thresholds of multitone sounds due to an error in the estimation of thresholds for single tones. Additional details may be found in a forthcoming NASA Technical Memorandum entitled “Audibility of Multiple, Low-Frequency Tonal Signals in Noise.”Predicting the audibility of a sound over ambient noise is an important step to assess its impact on observers. One anticipated need for such predictions is the desire to operate aerial vehicles in urban surroundings close to the public. The increased audibility of a complex set of low-frequency tones due to the recruitment of a number of independent auditory channels has been investigated in this work. Three experiments were carried out to establish a sensitivity rule for these signals. During the main experiment, the masked threshold for signals consisting of one, two, and three tone components (55, 120, and 200 Hz) were measured. As expected, the thresholds identified during this experiment point to an increased sensitivity relative to a single-tone case. However, these increases were greater than similar findings by other researchers at higher frequencies. Two follow-up experiments examined the effect of larger frequency separation between tones and their intermodulation. The findings of these experim...

Reduced multisensory facilitation in adolescents and adults on the Autism Spectrum

Individuals with autism are reported to integrate information from visual and auditory channels in an idiosyncratic way. Multisensory integration (MSI) of simple, non-social stimuli (i.e., flashes and beeps) was evaluated in adolescents and adults with (n = 20) and without autism (n = 19) using a reaction time (RT) paradigm using audio, visual, and audiovisual stimuli. For each participant, the race model analysis compares the RTs on the audiovisual condition to a bound value computed from the unimodal RTs that reflects the effect of redundancy. If the actual audiovisual RTs are significantly faster than this bound, the race model is violated, indicating evidence of MSI. Our results show that the race model violation occurred only for the typically-developing (TD) group. While the TD group shows evidence of MSI, the autism group does not. These results suggest that multisensory integration of simple information, void of social content or complexity, is altered in autism. Individuals with autism may not benefit from the advantage conferred by multisensory stimulation to the same extent as TD individuals. Altered MSI for simple, non-social information may have cascading effects on more complex perceptual processes related to language and behaviour in autism.

A teoria cognitiva da aprendizagem multimídia no desenvolvimento de atividades de alfabetização matemática

Este trabalho tem como objetivo discutir a importância do uso dos canais auditivo e visual no contexto da elaboração de materiais didáticos e atividades para sala de aula, voltados à alfabetização matemática. A metodologia consistiu na revisão de literatura de diversos trabalhos relacionados à Teoria Cognitiva da Aprendizagem Multimídia, visando destacar a aplicação dos princípios dessa teoria na apresentação de atividades de alfabetização matemática comumente usadas em sala de aula.

Effect of haptic feedback on a virtual lab about friction

BackgroundWith the increase in recent years of the utilization of multimedia devices in education, new haptic devices for education have been gradually adopted and developed. As compared with visual and auditory channels, the development of applications with a haptic channel is still in the initial stages. For example, it is unclear how force feedback influences an instructional effect of an educational application and the subjective feeling of users. MethodsIn this study, we designed an educational application with a haptic device (Haply) to explore the effects of force feedback on selflearning.Subjects in an experiment group used a designed application to study friction by themselves using force feedback, whereas subjects in a control group studied the same knowledge without force feedback. A post-test and questionnaire were designed to assess the learning outcomes. Results/ConclusionsThe experimental result indicates that force feedback is beneficial to an educational application, and using a haptic device can improve the effect of the application and motivate students.

Loudness–Duration Tradeoff in Ultrasonic Courtship Songs of Moths

Moths have evolved auditory channels under predation pressure from insectivorous bats that emit ultrasonic pulses for capturing prey, including moths. Tympanate moths perform evasive behavior in response to echolocation calls of bats, but they also utilize ultrasonic signals mostly generated by males close to an intended female mate in the context of courtship. Unlike calling songs used to advertise the presence and sexual attractiveness of the signaler, courtship songs need not always be acoustically conspicuous. Male courtship songs are predominantly soft but sufficient for detection by a nearby potential mate. Quiet courtship songs are thought to effectively avoid being eavesdropped by gleaning bats, acoustic parasitoids, and conspecific competitors, i.e., rival males. However, males of some moth species generate loud courtship songs. In the present study, the duration of courtship song, in addition to the sound level of the song was predicted to affect the likelihood of being perceived by eavesdroppers. Loud and lengthy courtship songs, which are easily exploited by eavesdroppers, would be expected to rarely evolve, because a female receiver close to a male emitting a conspicuous song would also be exposed to strong predation pressure. This study explored the relationship between the peak sound level and the duration of single song bouts in 26 moth species from the following families: Noctuidae, Erebidae, Crambidae, Pyralidae, and Geometridae. The softest and loudest songs with mean peak sound levels of 64 and 129dB peSPL had mean durations of 1900 and 312 ms, respectively, whereas the shortest and longest songs with mean durations of 110 and 8839 ms had mean peak sound levels of 102 and 74 dB peSPL, respectively. Thus, the peak sound level and duration of courtship song exhibited a significant negative relationship. Although the energetic cost of producing song and the size of the sound-producing organ might also affect the relationship, the data support the conclusion that acoustic moths have adaptively evolved ultrasonic courtship songs with properties between “soft-and-long” and “loud-and-short” to avoid eavesdroppers.

Effects of multisensory stop signals on alcohol-induced disinhibition in adults with ADHD.

Multisensory environments facilitate behavioral functioning in humans. The redundant signal effect (RSE) refers to the observation that individuals respond more quickly to stimuli when information is presented as multisensory, redundant stimuli (e.g., aurally and visually) rather than as a single stimulus presented to either modality alone. RSE appears to be because of specialized multisensory neurons in the superior colliculus and association cortex that allow intersensory coactivation between the visual and auditory channels. Our studies show that the disinhibiting effects of alcohol are attenuated when stop signals are multisensory (e.g., Visual + Auditory stop signals) versus unisensory (Roberts, Monem, & Fillmore, 2016). The present study expanded on this research to test the degree to which multisensory stop signals could also attenuate the disinhibiting effects of alcohol in those with attention-deficit hyperactivity disorder (ADHD), a clinical population characterized by poor impulse control. The study compared young adults with ADHD (n = 22) with healthy controls (n = 22) and examined the acute impairing effect of alcohol on response inhibition to stop signals that were presented as a unisensory (visual) stimulus or a multisensory (Visual + Auditory) stimulus. For controls, results showed alcohol impaired response inhibition to unisensory stop signals but not to multisensory stop signals. Response inhibition of those with ADHD was impaired by alcohol regardless of whether stop signals were unisensory or multisensory. The failure of multisensory stimuli to attenuate alcohol impairment in those with ADHD highlights a specific vulnerability that could account for heightened sensitivity to the disruptive effects of alcohol. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Evaluating methods of crossmodal matching for multimodal displays in younger and older adults

Abstract A limited number of multimodal studies incorporate crossmodal matching – matching the intensity of stimuli across different sensory modalities – which is an important step that can help account for individual differences in the perception of cue salience. This study evaluates three crossmodal matching methods in terms of how age, matching method, and modality combination may contribute to subject match variability. One method was based on the method of bracketing (MoB; participant zeroes in on a match) and two methods were based on the method of adjustment (MoA; participant directly controls the stimulus intensity). This study evaluated three different matching methods with younger adults (ages 18–30 years) and older adults (ages 50–69 years). Matched values (stimulus intensity chosen by the participant) and subjective data were collected. The findings from both studies support the need to incorporate crossmodal matching in multimodal studies, as the results showed high match variability (between-subject variability in matched values selected) when using the MoB, where participants seemed to rely more on their perception compared to the MoA interface. Compared to younger participants, older participants exhibited less variability for matches with modality combinations that included the tactile and auditory channel – suggesting that age may contribute to subject variability when matching with these sensory channels. Furthermore, very few significant differences were found between interfaces at higher intensities suggesting that the MoB may be a suitable alternative to the MoA because while variability was highest with the bracketing method, the findings show it may be a truer reflection of participants’ responses. These findings can help inform the design and development of a reliable crossmodal matching method for use in multimodal experiments.

Does embodied training improve the recognition of mid-level expressive movement qualities sonification?

This research is a part of a broader project exploring how movement qualities can be recognized by means of the auditory channel: can we perceive an expressive full-body movement quality by means of its interactive sonification? The paper presents a sonification framework and an experiment to evaluate if embodied sonic training (i.e., experiencing interactive sonification of your own body movements) increases the recognition of such qualities through the auditory channel only, compared to a non-embodied sonic training condition. We focus on the sonification of two mid-level movement qualities: fragility and lightness. We base our sonification models, described in the first part, on the assumption that specific compounds of spectral features of a sound can contribute to the cross-modal perception of a specific movement quality. The experiment, described in the second part, involved 40 participants divided into two groups (embodied sonic training vs. no training). Participants were asked to report the level of lightness and fragility they perceived in 20 audio stimuli generated using the proposed sonification models. Results show that (1) both expressive qualities were correctly recognized from the audio stimuli, (2) a positive effect of embodied sonic training was observed for fragility but not for lightness. The paper is concluded by the description of the artistic performance that took place in 2017 in Genoa (Italy), in which the outcomes of the presented experiment were exploited.

An Online P300 Brain–Computer Interface Based on Tactile Selective Attention of Somatosensory Electrical Stimulation

PurposeP300 component of event related potentials in response to visual and auditory stimulation has been widely used in brain–computer interfaces (BCI). In clinical applications, tactile stimulus based on somatosensory electrical stimulation is an alternative for patients with impaired vision or hearing. This study presents an online P300 BCI based on somatosensory electrical stimulation paradigm. P300 signals were elicited by tactile selective attention of electrical stimuli on four fingers.MethodsFifteen healthy subjects participated in this study. Participants’ task was to focus their attention on the target finger and count the number. The classification of P300 signals was performed by step-wise linear discriminate analysis.ResultsThe average classification accuracy of the somatosensory BCI was 79.81 ± 7.91%, with the information transfer rate at 4.9 ± 1.3 bits/min. The BCI performance on different time windows was also evaluated in the present study.ConclusionsOur results demonstrate the feasibility of employing somatosensory electrical stimuli to build a practical online P300 BCI without taxing the visual and auditory channel, providing a wider application prospect in clinical applications and daily life. We anticipate our diagram to be a starting point for more explorations on utilizing electrical somatosensory stimuli in conjunction with portable BCI for neural rehabilitation.

The Study of Implementation of the Otoacoustic Emission for Registration of the Medicamentous Influence on the Auditory Channel of Guinea Pigs

Out of the hundred infants from one to three children are born with hearing disorders or acquire it in the neonatal period.That is, when performing a screening, there is no identification of the disease, but the normal function of the hearing organ is confirmed or not confirmed.Among the important advantages of otoacoustic emissions is that this method is objective, that is, minimizes the possibility of a mistake due to the influence of the human factor on the research process. In addition, this method can be applied from the very first days of life, which gives it a rather tangible advantage over subjective methods for which the cooperation of the subject is required.One of the new methods for objective hearing research, which is actively used in audio practice, is the method of recording distortion product otosacoustic emission signals (DPOAE) generated by the structures of the cochlear of the inner ear spontaneously or in response to acoustic stimulation.Guinea pigs were used as a test subjects because their hearing organ bears high level of resemblance to the human one.The complex of the results of guinea pig hearing ability testing obtained with the usage of otosacoustic emission at the frequency of the product of distortion was considered in the study. Each reviewed situation was presented by a set of survey results for each ear of the eight guinea pigs at 6 frequencies - 2 kHz, 4 kHz, 6 kHz, 8 kHz, 10 kHz, 12 kHz, in general 96 results in the research.Guinea pigs, whose bodies have not been affected by medications, were consolidated in the control group (which is taken as a result of their normal hearing state). Thus, 40 experiments on guinea pigs under medical effects and one for the determination of normal value were performed. This paper presents 6 groups of experiments.The analysis of the results took place as follows: for each one of the frequencies used, the mean value of the amplitude was found, and definition of the deviation set the confidence interval for each experiment.A statistical analysis of the obtained results was also carried out using Student's t-criterion. The reason of its application was match of the results to samples of the normal distribution law.Subsequently, the results (including the "Norma") are compared with the criterion for passing the otoacoustic test, which is given by Ph.D. Y. K. Sokolov.In this paper were obtained experimental results of the study of the condition of the auditory channel of experimental subjects (guinea pigs), on which the directed effect of medicinal nature was carried out were estimated by applying the method of confidence intervals and their subsequent statistical analysis was conducted with the usage of the t-criterion of the Student in order to establish the possibility of using these methods for assessing the state of the auditory canal when using otosacoustic emissions at the frequency of the product of distortion.According to the analysis of the above results, it can be concluded that the numerical results obtained provide comprehensive information on the state of the hearing of the control group of animals, but they are not suitable for the purpose of evaluating the individual results of the study.From the statistical and actual results presented in the work it can be concluded that the sensitivity of the applied methods to the mean values in the frequency bands and the less sensitivity to the error values.Ref.10, fig.6, tabl. 4.

Functional reorganization of the conceptual brain system after deafness in early childhood.

The neurodevelopmental consequences of deafness on the functional neuroarchitecture of the conceptual system have not been intensively investigated so far. Using functional magnetic resonance imaging (fMRI), we therefore identified brain areas involved in conceptual processing in deaf and hearing participants. Conceptual processing was probed by a pictorial animacy decision task. Furthermore, brain areas sensitive to observing verbal signs and to observing non-verbal visual hand actions were identified in deaf participants. In hearing participants, brain areas responsive to environmental sounds and the observation of visual hand actions were determined. We found a stronger recruitment of superior and middle temporal cortex in deaf compared to hearing participants during animacy decisions. This region, which forms auditory cortex in hearing people according to the sound listening task, was also activated in deaf participants, when they observed sign language, but not when they observed non-verbal hand actions. These results indicate that conceptual processing in deaf people more strongly depends on language representations compared to hearing people. Furthermore, additionally enhanced activation in visual and motor areas of deaf versus hearing participants during animacy decisions and a more frequent report of visual and motor features in the property listing task suggest that the loss of the auditory channel is partially compensated by an increased importance of visual and motor information for constituting object knowledge. Hence, our results indicate that conceptual processing in deaf compared to hearing people is more strongly based on the language system, complemented by an enhanced contribution of the visuo-motor system.

Dynamic Facial Expressions Prime the Processing of Emotional Prosody.

Evidence suggests that emotion is represented supramodally in the human brain. Emotional facial expressions, which often precede vocally expressed emotion in real life, can modulate event-related potentials (N100 and P200) during emotional prosody processing. To investigate these cross-modal emotional interactions, two lines of research have been put forward: cross-modal integration and cross-modal priming. In cross-modal integration studies, visual and auditory channels are temporally aligned, while in priming studies they are presented consecutively. Here we used cross-modal emotional priming to study the interaction of dynamic visual and auditory emotional information. Specifically, we presented dynamic facial expressions (angry, happy, neutral) as primes and emotionally-intoned pseudo-speech sentences (angry, happy) as targets. We were interested in how prime-target congruency would affect early auditory event-related potentials, i.e., N100 and P200, in order to shed more light on how dynamic facial information is used in cross-modal emotional prediction. Results showed enhanced N100 amplitudes for incongruently primed compared to congruently and neutrally primed emotional prosody, while the latter two conditions did not significantly differ. However, N100 peak latency was significantly delayed in the neutral condition compared to the other two conditions. Source reconstruction revealed that the right parahippocampal gyrus was activated in incongruent compared to congruent trials in the N100 time window. No significant ERP effects were observed in the P200 range. Our results indicate that dynamic facial expressions influence vocal emotion processing at an early point in time, and that an emotional mismatch between a facial expression and its ensuing vocal emotional signal induces additional processing costs in the brain, potentially because the cross-modal emotional prediction mechanism is violated in case of emotional prime-target incongruency.

Discontinuity of early and late event-related brain potentials for selective attention in dichotic listening.

If a representation of an auditory attention channel was present in the auditory cortices but not in the subcortical structures, it would be predicted that the early event-related brain potential (ERP) would disagree with the late ERP in selective attention effects. To examine this idea, the present study recorded the auditory brain stem response (ABR) as an early ERP and also the negative difference, the processing negativity and the irrelevant positive difference waves as late ERPs during dichotic listening. Each participant experienced two dichotic conditions: (i) 500-Hz standard tones to the left ear and 1000-Hz ones to the right ear (L500/R1000), (ii) 1000-Hz standard tones to the left ear and 500-Hz ones to the right ear (L1000/R500). In a control task, participants performed visual detection and ignored auditory stimuli. Although the negative difference and processing negativity were found to be identical between the two dichotic conditions, the ABR demonstrated a significant difference between relevant and irrelevant tasks only for the L500/R1000 condition. A response preference to lower-frequency tones was found for behavioural measures and late ERPs but not for the ABR. These results suggest difficulty in representing attention channels in the auditory brain stem. In addition, a weak effect of dichotic sound combination in behaviours corresponded only with earlier ERPs.

Auditory Task Irrelevance: A Basis for Inattentional Deafness.

ObjectiveThis study investigates the neural basis of inattentional deafness, which could result from task irrelevance in the auditory modality.BackgroundHumans can fail to respond to auditory alarms under high workload situations. This failure, termed inattentional deafness, is often attributed to high workload in the visual modality, which reduces one’s capacity for information processing. Besides this, our capacity for processing auditory information could also be selectively diminished if there is no obvious task relevance in the auditory channel. This could be another contributing factor given the rarity of auditory warnings.MethodForty-eight participants performed a visuomotor tracking task while auditory stimuli were presented: a frequent pure tone, an infrequent pure tone, and infrequent environmental sounds. Participants were required either to respond to the presentation of the infrequent pure tone (auditory task-relevant) or not (auditory task-irrelevant). We recorded and compared the event-related potentials (ERPs) that were generated by environmental sounds, which were always task-irrelevant for both groups. These ERPs served as an index for our participants’ awareness of the task-irrelevant auditory scene.ResultsManipulation of auditory task relevance influenced the brain’s response to task-irrelevant environmental sounds. Specifically, the late novelty-P3 to irrelevant environmental sounds, which underlies working memory updating, was found to be selectively enhanced by auditory task relevance independent of visuomotor workload.ConclusionTask irrelevance in the auditory modality selectively reduces our brain’s responses to unexpected and irrelevant sounds regardless of visuomotor workload.ApplicationPresenting relevant auditory information more often could mitigate the risk of inattentional deafness.